Chemical Vapor Deposition of Amorphous Silicon Using Tetrasilane

Abstract

Hydrogenated amorphous-silicon films have been deposited by the plasma-free chemical-vapor-deposition method using tetrasilane (Si4H10) at temperatures as low as 350°C. The film deposited at 350°C and 9 Torr had hydrogen content as high as 15 at.%, optical bandgap of 1.78 eV, logarithmic ratio of photoconductivity (at a light intensity of 100 mW/cm2 under AM1 conditions) to dark conductivity of 3.2, activation energy of 0.78 eV and the Urbach tail slope as small as 56 meV. Thin-film transistors have been fabricated using the film deposited at 350°C. The electron mobility was 0.6 cm2/V s under as-deposited conditions.

Studying of silane thermal decomposition mechanism

“…The experimental rate of particle growth d(r)/dt (where r is the particle radius) obtained from Figure 5 for (when disilane and t ϭ 0.1 s trisilane have the concentrations close to maximal) was compared with W evaluated from (3). We also took into account that under deposition from trisilane the rate of silicon layer growth is approximately two times higher than under deposition from disilane [46,53]. For the estimation showed that neous decomposition of silane and disilane are also the same and equals to Ͻ 0.5%.…”

The adsorption of silane, disilane and trisilane on polycrystalline silicon: a transient kinetic study

“…Complete desorption of hydrogen from the formed, presumably very unstable, compounds up to monohydride species will indeed result in a surface with the same amount of active Si-H sites for all three silanes at the beginning of each pulse. However, this need not necessarily be true, as can be inferred from literature on plasma-free CVD growth of hydrogenated amorphous silicon layers [28]. These layers were grown in the same temperature region in which the TAP experiments have been performed.…”

Aerosol assisted atmospheric pressure chemical vapor deposition of silicon thin films using liquid cyclic hydrosilanes

“…Alternatively, using higher order silanes, via CVD and PECVD resulted in incremental benefits to deposition temperature, rate and efficiency at the lab-scale. This approach has not yet been scaled to manufacturing levels, possibly due to the inconsistency in silane vaporization [3][4][5][6][7][8]. For an example, Chung et al, studied Si film deposition using neopentasilane (NPS) via lowpressure CVD, and found enhanced growth rates [4].…”